請問CST MWS中periodic邊界條件是怎么用的

請問cst中periodic邊界條件是怎么用的，用時(shí)域求解器想模擬一個(gè)平面周期結(jié)構(gòu)，但是設(shè)為peridoic后報(bào)錯(cuò)說不能用，怎么回事？

CST MWS幫助文件《Boundary Conditions - Boundaries》。
CST White Paper《Boundary and Symmetry Conditions》。
報(bào)錯(cuò)的具體信息都不說？

Periodic: Connects two opposite boundaries with a definable phase shift such that the calculation domain is simulated to be periodically expanded in the corresponding direction. Thus, changing oneboundary to periodic always changes the opposite boundary to periodic as well.
If you select a periodic boundary condition you may enter a phase shift for this boundary in the Phase Shift/Scan Angle property page.
Simulating antenna models with periodic boundaries enables you to examine the near field influence among the single antennas. However, note that the resulting structure represents an infinite expanded antenna pattern. To obtain the farfield of a finite pattern structure based on identical elements of the single antenna model, please use the postprocessing possibility to define an antenna array derived by the law of pattern multiplication.
好像是只能仿真無限大的陣列，同時(shí)還要設(shè)置相位差，想要仿真有限大的陣列，使用后處理功能就可以了

謝謝各位了，我現(xiàn)在就是想用時(shí)域來模擬像fss那樣的結(jié)構(gòu)，但是不知道怎么設(shè)置端口和邊界條件。以為periodic和fss里的unit cell會(huì)差不多吶，但是不行。能不能給我一個(gè)用時(shí)域模擬像fss這樣結(jié)構(gòu)的例子?。坎粍俑屑?。

時(shí)域的怎么模擬都是有限大的。無限的只能是unit cell